shapelib: Rename nominal arg to rect from centre

This is the nominal location, around which the rectangle is
centred.  This makes it clearer exp. for the call sites elsewhere,
where this parameter is just the piece position.

Signed-off-by: Ian Jackson <ijackson@chiark.greenend.org.uk>

diff --git a/src/shapelib.rs b/src/shapelib.rs
index c6f8f0f185ed43af9eac4b26a0bfff812d07a599..934a05a8cbe67e6291eb12d0ae4dd5b655f2d7b8 100644 (file)
--- a/src/shapelib.rs
+++ b/src/shapelib.rs
@@ -647,14 +647,14 @@ pub struct RectShape { pub xy: PosC<f64> }
 impl RectShape {
   // Used by code elsewhere eg deck.rs for occultation boundaries etc.
   #[throws(CoordinateOverflow)]
-  pub fn rect(&self, centre: Pos) -> RectC<Coord> {
+  pub fn rect(&self, nominal: Pos) -> RectC<Coord> {
     let offset = (self.xy * 0.5)?;
     let offset = offset.try_map(
       |c| c.floor().to_i32().ok_or(CoordinateOverflow)
     )?;
     let rect = RectC{ corners:
       [-1,1].iter().map(|&signum| Ok::<_,CoordinateOverflow>({
-        (centre + (offset * signum)?)?
+        (nominal + (offset * signum)?)?
       }))
         .collect::<Result<ArrayVec<_,2>,_>>()?
         .into_inner().unwrap()
@@ -663,8 +663,8 @@ impl RectShape {
   }
 
   #[throws(CoordinateOverflow)]
-  pub fn region(&self, centre: Pos) -> Region {
-    Region::Rect(self.rect(centre)?)
+  pub fn region(&self, nominal: Pos) -> Region {
+    Region::Rect(self.rect(nominal)?)
   }
 }